I thought about this down at the health-centre today, then had a chat about it with some friends.
Has it ever occurred to you how much energy that goes to waste at health-centers and gyms? With fitness and training becoming more popular (in my country it's exploding in quantities) more people attend to training using exercise-machines. Now imagine if these machines were equipped with turbines and generators? For example, the treadmills. That'd sure create a good quantum of energy, not only to run the gym/health-centre, but as electricity for other things, such as households.
Especially in a gym that takes customers 24/7.
I guess it could be called human energy-source.
Wouldn't surprise me if it's already in use here and there, but I think it's a good concept.
What's your take on this?